I hold that a corporation does ill if it seeks profit in restricting production . . . or seeking to achieve monopoly by illegal . . . treatment of its competitors. . . . If, on the other hand, a corporation seeks profit solely by . .. treating the public . . . and its rivals fairly:then such a corporation is behaving well. It is an instrumentality of civilization operating to promote abundance by cheapening the cost of living so as to improve conditions everywhere throughout the whole community.